. >>> reporter: cal grad jill costello was just 22 when see died from lung cancer in 2010. but it's how she lived that lives on. >> i do think that last year of jill's life although it was her most difficult and most challenging, you know, in many ways it could be the best year of her life. she did so many wonderful amazing things and truly lived life to its fullest. >> up here. >> reporter: best friends since kindergarten in san francisco, jill costello and kelsey harrison now share another bond. >> i'm using my lungs to run from new york city to san francisco. >> reporter: the 24-year-old harvard grad is spreading a simple message. anyone can get lung cancer. even nonsmokers like jill. >> the reason that i'm doing this is for jill and so i have that drive and i think she is watching out for us and making sure we make it to the end safely. >> reporter: kelsey took off from times square on july 30th and has spent four months on the road. >> go, giants! > >> reporter: at the wheel, sydney ford who road crew with jill at cal. >> that's probably what i miss the most having tha